Summary

  • The closure of the Strait of Hormuz and sustained damage to Gulf refining capacity maintain Brent crude prices above $120 per barrel.
  • UK government fiscal interventions delay tax increases while strategic reserves prevent physical fuel shortages despite supply chain bottlenecks.
  • European aviation and household utility sectors absorb cascading wholesale price shocks through operational reductions and forecasted regulatory price cap increases.
  • Diplomatic negotiations over maritime transit control stall peace agreements, extending the probability of sustained energy market volatility through the end of 2026.

UK motorists and household energy consumers face sustained cost increases tied to three overlapping disruptions: the effective closure of the Strait of Hormuz, which normally carries 20% of global oil flows; damage to Gulf refining capacity; and a diplomatic deadlock that leaves both conditions unresolved. The UK government has delayed a planned fuel tax increase and deployed strategic reserves to prevent physical shortages. But these tools cannot prevent wholesale price volatility from flowing through to forecourt pumps and heating bills through the end of this year, forcing simultaneous adjustments across transport and utility sectors.

How Prices Jumped

Brent crude rose from $73 to a peak of $126 a barrel following the start of US-Israel military operations against Iran on 28 February 2026. UK petrol prices reached 158.5p a litre on 19 May. Analysts establish a consistent relationship: every $10 wholesale increase adds roughly 7p per litre at retail; the $53 rise translates to approximately 37p, consistent with observed forecourt movement through a two-week logistical lag. The RAC projects unleaded petrol will reach at least 160p unless crude prices fall substantially.

The disruption operates through two channels. Traffic through the Strait of Hormuz—which carries roughly 20% of daily global oil and gas flows—has fallen to a handful of transits daily from a pre-war baseline of 138, verified by BBC Verify and other independent monitoring. Simultaneously, Gulf refining capacity has sustained physical damage. Together, these mean global oil production remains largely intact, but the maritime transit routes and facilities converting crude into usable fuel have contracted. Infrastructure built over decades to maximize cost efficiency routed global supply through a single chokepoint, accepting the systemic risk of exactly this scenario: resolving the exposure requires generational infrastructure diversification.

What Policy Can Protect, and Cannot

Prime Minister Keir Starmer announced on 20 May the postponement of a 5p fuel duty increase from September to 31 December 2026. The package includes a cut to red diesel duty for farmers and rail, a 12-month vehicle excise duty holiday for heavy goods hauliers, and a £53 million support package for Northern Ireland and rural heating-oil households. No public record documents prior industry lobbying preceding the announcement. The December timing functions as a decision point rather than a fixed commitment—it coincides with end-of-year diplomatic and fiscal review cycles.

The government emphasizes preventing physical shortages through import diversification from the United States and Norway, alongside strategic reserves exceeding the 90-day requirement mandated by International Energy Agency obligations. The Department for Energy Security and Net Zero states oil accounts for 35% of total UK energy supply; independent analyses place direct primary consumption below 2%, suggesting the figure encompasses downstream transport dependencies.

But government cannot isolate UK pump prices from global wholesale volatility while transit remains blocked. Delaying a tax increase shields household finances for six months; releasing strategic reserves ensures petrol stations do not run dry. Neither addresses the root cause: without restored transit or refining capacity, wholesale turbulence transmits directly to retail prices through the logistical lag. The official market regulator found no evidence of retailers exploiting the conflict through pricing strategy changes.

Where the Shock Lands

Utility prices transmit wholesale volatility to households through regulatory mechanisms. Cornwall Insights forecasts the July energy price cap will rise 13% (approximately £209) to £1,850 annually for a typical dual-fuel household. The April cap fell, remained frozen through June, and the July reset captures partial catch-up to wholesale movement rather than full cost transmission. Sequential increases are possible in the October revision if crude prices remain elevated through autumn.

European jet fuel prices more than doubled following the conflict and currently sit roughly 50% above pre-conflict levels. European jet fuel reserves amount to approximately six weeks of supply. Airlines have responded with route cancellations and fare increases. The International Energy Agency encouraged demand-reduction measures including teleworking and car sharing, signaling the absence of near-term supply-side solutions.

What Would Reverse Prices

Diplomatic reporting indicates negotiations for a peace agreement have stalled, with control of the strait remaining “a major sticking point”. Iranian maritime operations restrict transit while the US-Israel coalition maintains military engagements to degrade Iranian logistical networks. The current disruption is transit-based: global oil production capacity is largely intact. Production-cut analogies such as the 1973 OPEC embargo do not apply.

Historical straits closures resolved through negotiation include the 1956 Suez Canal closure (approximately 6 months) and the 1967 closure (approximately 8 years). Supply recovery timelines extend beyond the diplomatic negotiation timeframe.

Probabilities Through Year-End

The probability of Strait of Hormuz reopening before July sits at 15–20% (low confidence; reference class n=3, median approximately 7 months from onset). By December, the probability increases to 35–45% (roughly 10 months post-onset, within the upper range if historical outliers are excluded), with 20–25% probability of extension into 2027 (moderate confidence, conditioned on stalled negotiations).

Brent crude remaining above $100 a barrel through year-end carries 75–80% probability (moderate-to-high confidence, anchored to JP Morgan projections and reference-class assessment of sustained supply disruptions with infrastructure damage). UK pump prices exceeding 170p a litre before resolution hold 55–65% probability (moderate confidence; requires sustained Brent pricing at $115–120 through the lag-adjusted window). Price declines depend on verified return of Gulf refining capacity, transit expansion toward baseline levels (an optimistic threshold rests at approximately 20 vessels daily, roughly 14% of pre-war flows), or formalized maritime access agreements. Escalation of naval engagements or ceasefire breakdown projects toward higher-end volatility bands.

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Analytical techniques used in this piece

This analysis applies the methods below. Each links to a short, plain-English explainer you can read and reuse.

Interest Mapping
Separates parties’ stated positions from their underlying interests (Fisher & Ury).
Probabilistic Forecasting
Puts calibrated probabilities on what happens next.
Root-Cause Analysis
Traces a symptom back along its causal chain to the conditions that actually generated it.
Creative Destruction
Innovation that grows the economy by dismantling the incumbents it displaces (Schumpeter).